1. Field of the Invention
This invention relates to an automatic original feeding device for feeding an original to an optical processing station by the use of conveying means which obtains a drive force by movement of an original carriage provided in an image forming apparatus. This invention also relates to an image forming apparatus provided with such automatic original feeding device.
2. Description of the Prior Art
Description will hereinafter be made by taking as an example an automatic original feeding device used in an electrophotographic copying apparatus.
As disclosed in U.S. Pat. Nos. 4,367,947 or 4,368,977, an automatic original feeding device for feeding an original to an exposure station by the use of a roller which obtains a rotational force by reciprocal movement of an original carriage is known. However, this known automatic original feeding device could well feed a thin sheet original to the exposure station, but could not adequately cope with a thick original such as a book original. That is, when a thick original is to be placed on a platen glass for the purpose of exposure, it has been necessary to leave the automatic original feeding device retracted from the platen glass and manually hold down the thick original. Or it has been necessary to hold down the thick original by a keep plate exclusively for use for thick originals which is provided discretely from the automatic original feeding device. This has led to a problem that the apparatus becomes bulky or the handling operation is cumbersome.